The drive belt on my Honda HRB215 keeps jumping off. I took the mower apart far enough to get at the belt and noticed the the drive pulley going into the transmission is wobbling around like the bearing is shot. But maybe it's supposed to do that??? what's the fix to keep the belt on.???

Keep in mind that the mower deck gets to be raised and lowered into the desired mowing height, with no change to drive pulley (at motor) height. This requires a belt long enough to allow the furthest reach (usually with deck dropped to lowest setting) and a spring loaded tensioner pulley, to take up the slack (and keep the belt tight) as the deck is raised. There may also be a belt guide or two incorporated to help keep the belt from jumping ship in the process. Sometimes these are just a heavy gauge steel wire loop that attaches near the pulley to keep the belt from jumping if it gets slack. Possibly you didn't thread the belt through or under it properly, or have missed the tensioner pulley.

It could also be the tensioner spring is broke or has fallen off or become too weak. Have someone move the deck up and down (with motor off, and belt installed) while you watch to see there is any obstruction in path. Also look for the belt becoming loose at a certain point. Some tensioners have the spring built in to the pulley and you can't really see them. They have to be pre-loaded, by rocking the pulley spindle assembly against the spring force while you slip the belt over it. Sometimes the belt looks fine and not loose in static (not moving) condition, but when the blades are spinning fast and the throttle is closed with no load (no thick grass being cut) the blades momentum will cause a belt sag that is supposed to be taken care of by the tensioner. It can get pretty grimy down there, also very dry, dusty and caked with cement like old clippings. Check the manual and find out where your tensioner is, then check it to make sure that it can move freely and it isn't locked tight by debris or rust. Also good to check if there has been an update to your mower. Sometimes these problems cause a manufacter to offer a better spring, or change pulley sizes to correct a common problem.

Wearing out a belt that fast must have a bad bearing or a misaligned pulley. Good luck.

Hi, check the idler pulley arm and return spring on that belt. Its most likely not pivoting freely allowing the belt to loosen when you operate the clutch, regards Phil.

the belt could be worn enough to allow it to jump off under a load or you may have a bad pulley in the series

You may have a bearing that is locked up, check to see if you can turn all the pulleys freely. If you cannot you may have to replace the one you can't.

Pulleys are not supposed to wobble. Maybe the shaft is bent. A bearing that is worn would allow the pulley to move to one side and would probably be noisy.
Gary

u could have a bent pulley ..

You can loosen the bolts that hold the pulleys and guards far enough to slip the belt in, then tighten them back up. I have also carefully bent the guides back just far enough for the belt to go in, then bent them back in place

check for a broken belt tension er or maybe grass clippings under belt area, check for a broken or loose pulley bearing, even a bent shaft on the deck.

Hi, this is a easy solution. on your drive pulley, there should be three belt keepers to keep the belt from coming off. ( belt keeper is a 1/4" dia. rod that goes over the pulley)